Basic HTML version of Foils prepared 21 October 1995

Foil 25 Circuit Switched Networks

From New CPS615 Foils-- B 28 August 95 CPS615 Basic Simulation Track for Computational Science -- Fall Semester 95. by Geoffrey C. Fox


Rather than have messages travel single hop at a time, sometimes circuit is first established from sender to receiver, and then data transmitted along circuit.
Similar to establishing phone connection
Can result in significantly lower communication overhead as latency deterministic once circuit established
If circuit blocked, many options possible, including
  • Retry, perhaps with alternative circuit or random delay
  • Wormhole routing: message travel like a wagon-train along path, stops when blocked but stays in circuit.
  • Virtual cut-through: message dumps into memory where forward progress blocked, then retries. Blend of pure circuit-switching and store-and-forward.
At high levels of message traffic, performance sometimes severely degraded.



© on Tue Oct 7 1997